1. Field of the Invention
This invention relates to an optically active .alpha.-cyano-3-(4-halogenophenoxy)benzyl 2-(4-chlorophenyl)-isovalerate of the formula (I): ##STR1## wherein X is a fluorine atom, a chlorine atom or a bromine atom, and * indicates an asymmetric carbon atom, which contains at least 60% of a compound of said formula having an (S)-configuration on both the acid and alcohol moieties; (S)-.alpha.-cyano-3-(4-halogenophenoxy)benzyl (S)-2-(4-chlorophenyl)isovalerate; a process for preparing the same; and an insecticide and/or acaricide containing the same.
2. Description of the Prior Art
.alpha.-Cyano-3-(4-halogenophenoxy)benzyl 2-(4-chlorophenyl)isovalerates are useful as insecticides and/or acaricides. These esters have one asymmetric carbon atom on each of the acid and alcohol moieties. An ester provided by the conventional method is a mixture comprising substantially equal amounts of four isomers.
These optical isomers are hereunder referred to as shown in Table 1 below.
TABLE 1 ______________________________________ Abbreviations for Optical Isomers Acid Moiety (S)-Config- (R)-Config- Alcohol Moiety uration Racemic uration ______________________________________ (S)-Configuration A.alpha.-Isomer .alpha.-Isomer B.alpha.-Isomer Racemic A-Isomer "Racemate" B-Isomer (R)-Configuration A.beta.-Isomer .beta.-Isomer B.beta.-Isomer ______________________________________
However, no single optical isomer which is optically active on both the acid and alcohol moieties has yet been synthesized, and as a matter of course, the relationship between the physiological activity and configuration has not been known.